Strong evidence for charge-density correlation in the underdoped phase of the cuprate YBa2Cu3Oy was obtained by NMR and resonant X-ray scattering. The fluctuations were found to be enhanced in strong magnetic fields. Recently, 3D charge-density–wave (CDW) formation with long-range order (LRO) was observed by X-ray diffraction in H 15 T. To elucidate how the CDW transition impacts the pair condensate, we have used torque magnetization to 45 T and thermal conductivity κxx to construct the magnetic phase diagram in untwinned crystals with hole density p = 0.11. We show that the 3D CDW transitions appear as sharp features in the susceptibility and κxx at the fields HK and Hp, which define phase boundaries in agreement with spectroscopic techniques. From measurements of the melting field Hm(T) of the vortex solid, we obtain evidence for two vortex solid states below 8 K. At 0.5 K, the pair condensate appears to adjust to the 3D CDW by a sharp transition at 24 T between two vortex solids with very different shear moduli. At even higher H (41 T), the second vortex solid melts to a vortex liquid which survives to fields well above 41 T. de Haas–van Alphen oscillations appear at fields 24–28 T, below the lower bound for the upper critical field Hc2.
展开▼
机译：通过核磁共振和X射线共振散射，获得了铜酸盐YBa2Cu3Oy掺杂不足相中电荷密度相关性的有力证据。发现在强磁场中波动会增强。最近，在H> 15 T中通过X射线衍射观察到具有长程（LRO）的3D电荷密度-波（CDW）形成。为阐明CDW过渡如何影响成对的凝析水，我们使用了扭矩磁化强度45 T和热导率κxx构成孔密度p = 0.11的未缠绕晶体的磁相图。我们显示3D CDW跃迁在HK和Hp场的磁化率和κxx中表现为尖锐的特征，这与光谱技术一致定义了相界。通过测量涡旋固体的熔融场Hm（T），我们获得了低于8 K的两个涡旋固态的证据。在0.5 K时，该对冷凝物似乎通过在24 T时在两个之间的急剧转变而适应了3D CDW。具有截然不同的剪切模量的涡旋固体。在更高的 H （41 T）下，第二个涡旋固体融化成涡旋液体，并在远高于41 T的磁场中幸存下来。de Haas–van Alphen振荡出现在24–28 T场，低于上限临界域 H c 2的下限。
展开▼
